From the Independent, 24/3/99, and article on Irish culture and speficially traditional music, that refers to the London Irish session scene and 'Paddy in the Smoke':

For the social historian Reg Hall, however, Irish music isn't what it was. Hall is giving an illustrated lecture at the Barbican on Saturday entitled "Paddy in the Smoke", which will look at the heyday of Irish music in London in the Fifties and Sixties. "The music in the pub scene of London then was a transplantation of rural music from the West of Ireland, and it began after the war as a new phenomenon, for traditional music was never played in Irish pubs at that time," Hall says.

"What you had then was tens of thousands of Irishmen living in London, mostly from the rural West and South. As mainly labourers working on the building sites, they evolved a whole social system in the Irish settlements of Kilburn, Paddington, Kentish Town and Dalston, and also in Hammersmith and Fulham, where they colonised run-down pubs. In those days, none of the Irish professionals working for Aer Lingus or the Irish banks would be seen dead there, for they regarded the musicians as louts. It was instrumental music, with fiddle, flute and accordion, and piano and drums added if it was a dance. There was no guitar, never mind a bouzouki, and the name "bodhran" hadn't even been coined. It was still a tambourine."